UTILIZATION or IONIZING ENERGY
213
INSECT
DEINFESTATION
'
The third general area wherein ionizing energy and dehydrates have common unit opera—
tions is in the deinfestation of cereals, cereal bars, cocoa bars, etc. The practicability of
using electrons for the deinfestation of packaged military rations as well as the determina—
tion of the dose requirements for a number of insects and the several stages of their development was shown by Proctor, Lockhart, Goldblith, Grundy, Tripp, Karel, and Broglé (1954).
The dose requirements are minimal (under 50,000 rad), and this method has been approved
by the U. S. Food and Drug Administration for the deinfestation of wheat and wheat
products in a regulation issued on August 21, 1963.
'
STERILIZATION
OF
ENZYMES
AND
PHARMACEUTICALS
The fourth aspect of the use of ionizing energy in dehydrates relates to the sterilization of
enzymes and other products of bacterial metabolism such as the antibiotics. It was established some years ago that enzymes are a"ected mainly indirectly in contrast to microor—
ganisms being destroyed mainly by direct hits. This subject is reviewed very well in Lea’s
famous book, ACTIONS OF RADIATIONS ON LIVING CELLS (1947).
The up—to—date literature on the effect of radiations on enzymes is summarized very
well in the following texts : Haissinsky (1955), Bacq and Alexander (1955), Grosch (1965),
Ebert and Howard (1963), and in Symposia in Biology, Number 14, of the Brookhaven _,—
National Laboratory (1961).
The literature on the effects of ionizing energy on enzymes shows that :
1. Enzymes in dilute solution are relatively radiosensitive, and the action of ionizing
energy on enzymes is mediated via free radical and activated molecules.
2. Enzymes «in situ» in foodstus are thus relatively radioresistant, and although some
portion of the enzymes in foods are destroyed by radiation, many enzymes remain
even after dosages of 10 megarad. (T hus in food sterilization by ionizing energy,
means other than the radiation itself mustbe found to inactivate enzymes in the foods.)
3. Enzymes in the dry state are affected mainly by direct hits on the molecules thus
relatively little loss in activity is evidenced.
4. Pharmaceutical products react in a manner similar to enzymes in terms of radiation
response on a quantitative basis.
_
In view of the above, enzymes and pharmaceuticals have been sterilized by ionizing
energy with relatively little loss in potency, and this method has been used to some degree
in the medical eld (Artandi and Van Winkle, 1959; Miller, 1954; Grainger and Hutchmson,
1957; Controulis, Lawrence, and Brownell, 1954; and Colovas, 1955). As the production
of many of the antibiotics utilize dehydration in the production program, this method of
sterilization offers interesting possibilities. Further, inasmuch as a number of enzymes
are now being produced by mold and bacterial metabolism
followed by separation, pun—
cation, and dehydration, a terminal means of ster1hzatmn of these may be of interest.
213
INSECT
DEINFESTATION
'
The third general area wherein ionizing energy and dehydrates have common unit opera—
tions is in the deinfestation of cereals, cereal bars, cocoa bars, etc. The practicability of
using electrons for the deinfestation of packaged military rations as well as the determina—
tion of the dose requirements for a number of insects and the several stages of their development was shown by Proctor, Lockhart, Goldblith, Grundy, Tripp, Karel, and Broglé (1954).
The dose requirements are minimal (under 50,000 rad), and this method has been approved
by the U. S. Food and Drug Administration for the deinfestation of wheat and wheat
products in a regulation issued on August 21, 1963.
'
STERILIZATION
OF
ENZYMES
AND
PHARMACEUTICALS
The fourth aspect of the use of ionizing energy in dehydrates relates to the sterilization of
enzymes and other products of bacterial metabolism such as the antibiotics. It was established some years ago that enzymes are a"ected mainly indirectly in contrast to microor—
ganisms being destroyed mainly by direct hits. This subject is reviewed very well in Lea’s
famous book, ACTIONS OF RADIATIONS ON LIVING CELLS (1947).
The up—to—date literature on the effect of radiations on enzymes is summarized very
well in the following texts : Haissinsky (1955), Bacq and Alexander (1955), Grosch (1965),
Ebert and Howard (1963), and in Symposia in Biology, Number 14, of the Brookhaven _,—
National Laboratory (1961).
The literature on the effects of ionizing energy on enzymes shows that :
1. Enzymes in dilute solution are relatively radiosensitive, and the action of ionizing
energy on enzymes is mediated via free radical and activated molecules.
2. Enzymes «in situ» in foodstus are thus relatively radioresistant, and although some
portion of the enzymes in foods are destroyed by radiation, many enzymes remain
even after dosages of 10 megarad. (T hus in food sterilization by ionizing energy,
means other than the radiation itself mustbe found to inactivate enzymes in the foods.)
3. Enzymes in the dry state are affected mainly by direct hits on the molecules thus
relatively little loss in activity is evidenced.
4. Pharmaceutical products react in a manner similar to enzymes in terms of radiation
response on a quantitative basis.
_
In view of the above, enzymes and pharmaceuticals have been sterilized by ionizing
energy with relatively little loss in potency, and this method has been used to some degree
in the medical eld (Artandi and Van Winkle, 1959; Miller, 1954; Grainger and Hutchmson,
1957; Controulis, Lawrence, and Brownell, 1954; and Colovas, 1955). As the production
of many of the antibiotics utilize dehydration in the production program, this method of
sterilization offers interesting possibilities. Further, inasmuch as a number of enzymes
are now being produced by mold and bacterial metabolism
followed by separation, pun—
cation, and dehydration, a terminal means of ster1hzatmn of these may be of interest.